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Dec. 3, 2009 -- Scientists say they could find no substantial change in the
incidence trend of brain tumors among a study group of 60,000 people five to 10
years after cell phone usage rose sharply in the countries where they
lived.

Cell phones have been mentioned for years as possible causes of brain
tumors, but the new study, published in the Dec. 3 online issue of the
Journal of the National Cancer Institute, found no cell phone-related
increase during this study period.

Researchers from Denmark, Finland, Norway, and Sweden say they found that
the incidence of brain tumors in the studied population of people from the four
countries remained stable, decreased, or showed only a gradual increase that
started before the introduction of the wireless devices between 1974 and
2003.

Mobile phone use in those Nordic countries rose dramatically in the
mid-1990s, the study says.

Lead author Isabelle Deltour, PhD, of the Institute of Cancer Epidemiology
of the Danish Cancer Society, and colleagues say they found no change in
incidence trends of brain tumors in data going back to 1998.

They mentioned several possible reasons for their finding:

The induction period relating cell phone use to brain tumors exceeds five
to 10 years;

The increased risk is too small to be observed;

The increased risk is restricted to subgroups of brain tumors or cell phone
users;

There is no increased risk of brain cancer by using cell phones.

The authors say they didn’t examine cell phone usage at the individual level
during the time period studied, only the incidence of brain tumors.

“Because of the high prevalence of mobile phone exposure in this population
and worldwide, longer follow-up trends in brain tumor incidence are warranted,”
the authors write.

The U.S. Food and Drug Administration says on its Web site that “The weight
of scientific evidence has not linked cell phones with any health
problems.”

The agency continues to monitor findings of new and ongoing studies. The
federal agency says that wireless phones emit low levels of radiofrequency
energy. This is different than radiation from X-rays.

The American Cancer Society says that in looking at most studies as a whole,
no link between cell phones and tumor development has been found.

Deltour and colleagues, who studied data on 59,984 men and women aged 20-79
diagnosed with brain tumors, say that if there is a linkage between the disease
and cell phone use, the numbers don’t reveal it.

"Our finding that brain tumor incidence rates were either stable, decreased,
or continued a gradual increase that started before the introduction of mobile
phones is consistent with mobile phone use having no observable effect on brain
tumor incidence…,” the authors conclude.

They add that population groups that are heavy mobile phone users should be
studied for longer periods of time.

Michael Thun, MD, vice president emeritus, of the ACS, tells WebMD that
“this is a good study” that “clearly shows the incidence” of brain tumors
doesn’t increase after a period of five to 10 years.

However, he says more research needs to be done to see if longer-term use
can cause tumors.

"That’s important, because it’s an incredibly widely-used technology,” he
says. “The study doesn’t answer the question of what happens after 50
years.”

John Walls, a vice president of the mobile industry trade group, CTIA-The
Wireless Association, says “peer-reviewed scientific evidence has
overwhelmingly indicated that wireless devices do not pose a public health
risk” and that the ACS, the NCI, the World Health Organization and the U.S.
Food and Drug Administration “all have concurred that wireless devices are not
a public health risk.”